As disclosed in the Brazilian patent application BR 10 2013 004382-6 of the same applicant, gains in energy efficiency, in improved drivability and in the reduction of pollutant emission may be achieved by a thermal management system for the feeding of fuel in an internal combustion engine, which is capable to maintain the fuel at a temperature more adequate to combustion upon being fed to the engine. The thermal management system includes a heat exchanger which uses, as a heat source, the thermal energy dissipated by the engine, without requiring extra generation of energy.
One of the means to dissipate thermal energy is the vehicle radiator, which comprises a heat exchanger for cooling the engine, avoiding its overheating, by the thermal exchange of the engine and components thereof to the atmosphere, through the radiator of the vehicle and using water as an intermediate fluid.
However, the heat transmitted from the engine to the water of the radiator is a lost and even undesirable energy, since if said heat stays stored in the water, the latter loses efficiency as a thermal exchange fluid. The cooler the water of the radiator, the higher the amount of heat the water is capable to absorb from the engine, in a shorter time interval.
Another known means for dissipating the thermal energy of the engine is the lubricant oil itself which, besides lubricating the movable parts of the engine, allows the heat generated by the latter to be conducted to the outside of the engine and dissipated in the atmosphere. Some parts of the engine, such as the crankshaft, bearings, camshaft, rods and pistons, can be cooled only by the lubricant oil of the engine. When overheated, the oil loses its viscosity, is susceptible to deteriorations and consequently, loses its expected lubricating properties, as well as the capacity to cool the internal parts of the engine, impairing the proper operation of the engine components, causing severe damages or even loss of the vehicle engine.
Some vehicles, particularly heavy vehicles, are provided with an oil radiator, which takes the form of a heat exchanger, usually of the plate type, provided between the block of the engine and the necessary oil filter, usually downstream the latter, or even incorporated, in a single block, to the oil filter, as it usually occurs in heavy vehicles, in order to operate as an enhancer for the thermal exchange between the lubricant oil and the water of the radiator. However, the oil radiators presently used do not carry out thermal exchange between the oil and the fuel.
Thus, as discussed in said prior patent application BR 10 2013 004382-6, in low temperature environments, in which the fuel has its temperature reduced to values inferiorly distant from the its flashpoint (“cold fuel”), there is a greater or lesser difficulty in burning the fuel fed to the engine, which difficulty is more intensified with the use of fuels having a high flashpoint.
It should also be noted that the typical pressure in the interior of a fuel distributor in vehicles 1.0 L, having indirect injection, is of about 4.2 bar, a condition in which the vaporization temperature of the fuel is higher than its vaporization temperature under atmospheric pressure. For vehicles having direct fuel injection, these values (pressure and vaporization temperature) are further increased.
It is also known that the increase in the fuel temperature facilitates achieving a fuel spray of micrometric droplets, which will burn more easily when in contact with the spark from the ignition coil in the combustion chamber, or when they are compressed at a certain pressure (diesel).
Although the thermal exchange carried out between the heat dissipated by the running engine and the fuel is sufficient, in principle, to adequately heat a somewhat “cold” fuel, this is not a working condition which presents an optimized thermo-energetic efficiency, for it allows the occurrence of engine faults, jolts, engine slow acceleration response and emission of pollutants due to a deficient fuel burning.
In “flex vehicles” (driven by ethanol and/or gasoline in any mixture proportion) it is known that the engine yield is not optimized. An effective heating system may promote optimized conditions upon taking the fuel (for example, ethanol or gasoline) to better burning conditions (by heating the fuel to temperatures closer to the vaporization point thereof) and to a consequent better yield of the engine.
As a function of the above, it was proposed, in the previous patent application BR 10 2013 004382-6, a fuel heating management system, to be maintained operating during the entire time the engine is running, aiming at obtaining high performance (energetic optimization) of the engine, better vehicle handling, with fast responses when pressing the accelerator pedal, with optimized torque and power and with lower pollutant emissions, not only in “flex” type vehicles (two or three fuels), but also in vehicles provided with an internal combustion engine running on any fuel, liquid or gaseous.
One of the solutions proposed in said prior patent application, specifically the one illustrated in FIG. 3, comprises a management system for the feeding of fuel which is capable to absorb, by means of a common heat exchanger, the desired thermal energy both from the cooling water flow and from the lubricating oil flow of the engine. However, said prior patent application does not limit the invention to one type of heat exchanger which may be applied to the thermal management system, in order to use, when necessary, the heat which is dissipated by the flows of cooling water and of lubricant oil which are heated in the interior of the engine and conducted to the water and oil radiators, respectively.